Former Aide's Role in First-Primary State Could Help Governor if He Runs in 2016

MANCHESTER, N.H.—He's a 25-year-old political strategist known for his youthful appearance, calm demeanor and ability to manage campaigns from a futon while still a Rutgers University student. Now he runs the Republican Party in the first presidential primary state.

Meet Matt Mowers, a former aide to New Jersey Gov. Chris Christie who recently became the executive director of the New Hampshire Republican State Committee. It is a...